To make room for Rosscup on the 40-man roster, outfielder Dave Sappelt was designated for assignment.

All four players will be available for the Cubs tonight against the Miami Marlins at Wrigley Field. Grimm will wear uniform number 52 and Rosscup, who joins the first big league roster of his pro career, will wear uniform number 59.

Grimm, 25, was acquired from Texas on July 22 as part of the trade that sent Matt Garza to the Rangers. Prior to the trade, Grimm had spent nearly the entire 2013 season at the major league level, going 7-7 with a 6.37 ERA (63 ER/89.0 IP) in 17 starts with Texas. He was named the American League Rookie of the Month for April after going 2-0 with a 1.59 ERA (3 ER/17.0 IP) in three starts, fanning 15 and walking only four.

The righthander joined Iowa after the trade and went 2-3 with a 4.68 ERA (22 ER/42.1 IP) in eight starts. He finished his campaign strong, going 2-1 with a 2.76 ERA (9 ER/29.1 IP) in his final five starts.

Grimm made his big league debut last season thanks to a combined 11-6 record with a 2.81 ERA (42 ER/134.2 IP) in 25 appearances (22 starts) between Double-A Frisco and Triple-A Round Rock. He earned Texas League mid-season All-Star honors last year. Grimm is 8-8 with a 6.73 ERA (77 ER/103.0 IP) in 22 big league appearances, 19 as a starter, covering the last two seasons. Overall in his minor league career, Grimm is 21-12 with a 3.28 ERA (118 ER/323.1 IP) in 59 appearances (56 starts).

Raley, 25, returns for his third stint with the Cubs this season. He made one appearance during his previous two stops, allowing two runs in a 4.1 inning relief appearance vs. the Angels on July 10. With Iowa this season, Raley went 8-10 with one save and a 4.46 ERA (70 ER/141.1 IP) in 27 appearances (25 starts), allowing two earned runs or less in six of his final eight starts.

The southpaw made his big league debut with the club last August and went 1-2 with an 8.14 ERA (22 ER/24.1 IP) in five starts.

Boscan, 33, returns for his second stint with the Cubs this season. He spent August 8-10 with the club but did not appear in a game. Boscan spent parts of the last three seasons with the Braves (2010-12), posting a career .263 batting average (5-for-19) in 11 major league contests. The 2013 campaign marks the 17th professional season for the right-handed hitting catcher. He made his big league debut with the Braves on October 1, 2010 after 976 minor league games spanning 14 seasons.

The Venezuelan native batted .232 (54-for-233) with nine doubles and 18 RBI in 74 games with Iowa this season. Boscan was a non-roster invitee to spring training with the Cubs after signing a minor league deal last November. He originally signed with the Braves as a non-drafted free agent on July 2, 1996, and has played in the Atlanta (1997-2005, 2008-12), Milwaukee (2006), Cincinnati (2007) and Cubs organizations.

Rosscup, 25, is poised to make his major league debut after combining to go 2-2 with three saves and a 2.12 ERA (12 ER/51.0 IP) in 46 relief appearances between Double-A Tennessee and Triple-A Iowa, his first full season pitching exclusively in relief. He struck 83 batters in 51.0 innings pitched, an average of 14.2 strikeouts per nine innings, while limiting all foes to a .195 batting average (36-for-185). Rosscup allowed two homers in 51.0 innings.

The southpaw began the season with Tennessee, where he went 2-1 with three saves and a 2.49 ERA (12 ER/43.1 IP) in 37 outings to earn his first-ever promotion to Triple-A. With Iowa, Rosscup did not allow an earned run in nine appearances, striking out 17 in 7.2 innings pitched.

Rosscup was acquired by the Cubs as part of the eight-player trade that brought Matt Garza to Chicago on January 8, 2011. The Clackamas, Ore. native was originally selected by Tampa Bay in the 28th round of the 2009 Draft. In five minor league seasons, Rosscup is 14-10 with four saves and a 2.62 ERA (63 ER/216.2 IP) in 94 minor league appearances (27 starts). He is the second player from Chicago's inaugural 2013 Rookie Development program to reach the big leagues, joining teammate Logan Watkins.